U.S. patent number 4,359,615 [Application Number 06/292,440] was granted by the patent office on 1982-11-16 for switch and means to prevent unauthorized operation thereof.
This patent grant is currently assigned to Black & Decker Inc.. Invention is credited to Carl E. Meyerhoefer, Carl H. Meyerhoefer.
United States Patent |
4,359,615 |
Meyerhoefer , et
al. |
November 16, 1982 |
Switch and means to prevent unauthorized operation thereof
Abstract
A switch actuator in the form of a bifurcated elongated member
has a pair of legs pivoted relative to each other. In the "off"
position of the switch, the legs may be pivoted relative to each
other, and the actuator may be withdrawn from the switch. This
precludes an unauthorized operation of the switch and the equipment
controlled thereby. In the "on" position of the switch, an
interlocking means precludes the relative pivotal movement of the
legs, and the actuator may not be withdrawn from the switch. In the
preferred embodiment, the legs of the actuator automatically engage
an operating element of the switch, upon the insertion of the
actuator into the switch. Thereafter, the actuator has a limited
sliding movement to alternately move the switch into its "on" and
"off" positions. Preferably, the switch is of the "pull on/push
off" type; and the sliding movement of the actuator is in a plane
which is substantially parallel to the linear movement of the
switch operating element. Additionally, the actuator is provided
with an enlarged outer portion to facilitate manipulation by the
operator.
Inventors: |
Meyerhoefer; Carl E. (Little
Neck, NY), Meyerhoefer; Carl H. (Dix Hills, NY) |
Assignee: |
Black & Decker Inc.
(Newark, DE)
|
Family
ID: |
23124685 |
Appl.
No.: |
06/292,440 |
Filed: |
August 14, 1981 |
Current U.S.
Class: |
200/43.07;
200/330; 200/334 |
Current CPC
Class: |
H01H
27/08 (20130101) |
Current International
Class: |
H01H
27/00 (20060101); H01H 27/08 (20060101); H01H
009/20 () |
Field of
Search: |
;200/42R,42T,44,334,5R,330,331 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Shepperd; John W.
Attorney, Agent or Firm: Murphy; Edward D. Ottensen; Walter
Weinstein; Harold
Claims
We claim:
1. In combination with a switch having an operating element with
respect "on" and "off" positions, switch actuating means to prevent
unauthorized operation of the switch, said means comprising a
bifurcated elongated member slidably received within the switch,
said bifurcated elongated member having respective legs, means for
pivoting the legs relative to each other, the legs having
respective first and second portions on opposite sides of the
pivoting means, resilient means urging the respective first
portions of the legs apart and the respective second portions of
the legs together, means allowing the bifurcated elongated member
to be slidably inserted into the switch, means operative upon the
insertion of the bifurcated elongated member into the switch for
engagement of the respective second portion of at least one of the
legs with the operating element of the switch, the bifurcated
elongated member thereafter having a limited sliding movement
relative to the switch for moving the operating element between the
respective "on" and "off" positions of the switch, means for
preventing withdrawal of the bifurcated elongated member from the
switch in the "on" position of the switch, means operative in the
"off" position of the switch for allowing the respective first
portion of at least one of the legs of the bifurcated elongated
member to be pivoted towards the respective first portion of the
other leg of the member, and against the force of the resilient
means, and concurrently pivoting the respective second portion of
said one leg away from the respective second portion of said other
leg, thereby disengaging the bifurcated elongated member from the
switch operating element, and whereby the bifurcated elongated
member thereafter may be slidably withdrawn from the switch,
thereby precluding an unauthorized operation of the switch.
2. The combination of claim 1, wherein each of the legs is molded
from a suitable plastic material.
3. The combination of claim 1, wherein the pivoting means comprises
a boss formed on each of the legs between the respective first and
second portions thereof, each boss extending laterally away from
its leg towards the other leg, the bosses being formed
complementary to each other and having a nesting engagement with
each other, and a pin extending between the bosses.
4. The combination of claim 1, wherein the resilient means
comprises a torsion spring lodged between the respective first
portions of the legs.
5. The combination of claim 4, wherein the torsion spring has a
bight portion and respective leg portions extending therefrom, the
bight portion being disposed adjacent to the pivoting means for the
legs of the bifurcated elongated member, and the respective first
portions of the legs of the bifurcated elongated member each having
a blind longitudinal slot formed therein for receiving a respective
leg portion of the spring.
6. The combination of claim 1, wherein the resilient means
comprises a leaf spring formed integrally on a respective first
portion of one of the legs of the bifurcated elongated member, the
end of the leaf spring bearing against the respective first portion
of the other leg of the bifurcated elongated member.
7. The combination of claim 1, wherein the respective first portion
of the said one leg has an arcuate transverse projection, and
wherein the respective first portion of the said other leg has a
complementary arcuate recess, the arcuate projection and recess
being formed along a radius from the pivot means between said legs,
thereby facilitating the relative pivotal movement between the
legs.
8. The combination of claim 1, wherein the switch is mounted in the
housing of a power-operated device, and wherein a switch box is
mounted externally of the housing to at least partially enclose the
switch.
9. The combination of claim 8, wherein the switch box has a front
wall provided with an outer boss projecting therefrom and an inner
boss projecting therein, the inner boss being formed as a partial
continuation of the outer boss, and the outer boss having a
longitudinal slot formed therein, and wherein a complementary
longitudinal ridge is formed on said other leg of the bifurcated
elongated member and is received in the longitudinal slot, thereby
facilitating the slidable insertion of the bifurcated elongated
member through the switch box to engage the switch.
10. The combination of claim 9, wherein the outer boss has a side
wall adjacent to the longitudinal slot formed therein, and the
inner boss has a side wall formed as a continuation of the side
wall of the outer boss, and wherein said other leg of the elongated
bifurcated member has a flat surface adjacent to its longitudinal
ridge, the flat surface bearing against the respective walls of the
bosses as the elongated bifurcated member is slidably inserted into
the switch box.
11. The combination of claim 10, wherein the said other leg is held
against pivotal movement by engagement of its longitudinal ridge
within the complementary longitudinal slot, and wherein only the
said one leg member is pivotably movable to facilitate insertion
and withdrawal of the bifurcated elongated member through the
switch box to engage the switch.
12. The combination of claim 9, wherein only said one leg of the
bifurcated elongated member is pivotably moveable, the said other
leg being restrained against pivotal movement, and wherein the said
other leg has an integrally-formed outer operating portion
engageable by the operator for moving the switch from its "off"
position into its "on" position, and vice-versa.
13. The combination of claim 12, wherein the switch is of the
"push-off, pull-on" type and requires a deliberate movement to pull
the operating portion away from the switch box to turn the switch
"on", and wherein only a simple push on the operating portion is
required to turn the switch "off".
14. The combination of claim 13, wherein the said operating portion
has a substantially rectangular plan outline, and wherein the said
operating portion confronts the respective edges of the outer boss
of the switch box and is normally disposed adjacent thereto in the
"off" position of the switch, the dimensions of the said operating
portion being greater than the corresponding dimensions of the
outer boss, whereby the outer operating portion extends laterally
beyond the boss and substantially parallel to the outer surface of
the switch box.
15. The combination of claim 14, wherein the said operating portion
of the said other leg has a longitudinal side edge with a blind
transverse recess formed therein, the recess terminating in an
arcuate cut-out adjacent to the longitudinal side edge, and wherein
the said one leg has a respective outer operating portion disposed
in a plane substantially at right angles to the sliding movement of
the bifurcated elongated member, the respective operating portion
of the said one leg being nested partially in the blind transverse
recess of the said operating portion of the said other leg, and
being accessible via the arcuate cutout therein, whereby the
respective operating portion of the said one leg may be engaged by
the operator's thumb to move the respective operating portion
laterally and further into the blind transverse recess in the said
operating portion of the said other leg, thereby pivoting the said
one leg towards the said other leg, against the force of the
resilient means, to facilitate withdrawal of the bifurcated
elongated member in the "off" position of the switch.
16. The combination of claim 1, wherein only one of the legs of the
bifurcated elongated member has a pivotal movement, the other leg
being restrained against pivotal movement, and wherein the means
operative upon the insertion of the bifurcated elongated member
into the switch for engagement of at least the respective second
portion of said one leg with the operating element of the switch
comprises a transverse chamfer formed on the end of the respective
second portion of the said one leg, the respective second portion
of the said other leg having an end confronting the transverse
chamfer, the transverse chamfer terminating in a recessed
transverse notch formed in the said one leg, whereby, as the
bifurcated elongated member is inserted into the switch, the switch
operating element is received between the transverse chamfer on the
said one leg and the confronting end of the said other leg, thereby
pivoting the said one leg, and whereby, as the bifurcated elongated
member is further inserted into the switch, the transverse chamfer
rides over the switch operating element, and the switch operating
element is thereafter received within the recessed transverse notch
as the said one leg pivots in an opposite direction, the
cooperation of the switch operating element with the transverse
chamfer and recessed transverse notch, together with the resilient
means between the legs, thereby enabling the switch operating
element to be automatically engaged with a "snap" action as the
bifurcated elongated member is inserted fully within the
switch.
17. The combination of claim 1, wherein only one of the legs of the
bifurcated elongated member has a pivotal movement, the other leg
being restrained against pivotal movement, and wherein the means
for preventing the withdrawal of the bifurcated elongated member in
the "on" position of the switch comprises, a switch housing having
a pair of parallel longitudinal slots formed therein, one of the
slots being open and the other closed, a transverse pin carried by
the respective first portion of the said one leg of the bifurcated
elongated member, the pin being substantially parallel to the pivot
axis, and the pin having at least one portion extending beyond the
said one leg, whereby in the "off" position of the switch, the said
one leg may be pivoted to enable the extending portion of the pin
to be received in the open slot, whereby the bifurcated elongated
member may thereafter be withdrawn from the switch, and whereby in
the "on" position of the switch, the extending portion of the pin
is received in the closed slot to preclude pivotal movement of the
said one leg, thereby preventing withdrawal of the bifurcated
elongated member from the switch in the "on" position of the
switch.
18. In combination with a switch having an operating element with
respective "on" and "off" positions, switch actuating means to
prevent unauthorized operation of the switch, said means comprising
a bifurcated elongated member, means allowing the member to be
slidably inserted into the switch, means operative upon the full
insertion of the member within the switch for coupling engagement
between the member and the switch operating element, the member
thereafter having a limited slidable movement relative to the
switch for moving the operating element between the respective "on"
and "off" positions of the switch, the member having a pair of legs
pivoted relative to each other, resilient means biasing the pivoted
legs to a first position relative to each other, means operative in
the "off" position of the switch for allowing the legs to be
pivoted against the resilient means and into a second position
relative to each other for thereafter withdrawing the bifurcated
elongated member out of the switch, thereby precluding an
unauthorized operation of the switch, and means for preventing the
relative pivotal movement between the legs to preclude withdrawal
of the bifurcated elongated member in the "on" position of the
switch.
19. In combination with a switch having an operating element with
respective "on" and "off" positions, the operating element
comprising a slide button moving linearly in a given plane, switch
actuating means to prevent unauthorized operation of the switch,
said means comprising an elongated non-rotatable switch actuator,
means allowing the switch actuator to be slidably inserted into the
switch along a plane substantially parallel to the plane of
movement of the slide button, resiliently-biased means
automatically operative upon the slidable insertion of the
elongated switch actuator for effecting a "snap action" engagement
between the actuator and the slide button, the actuator thereafter
having a limited sliding movement in a plane substantially parallel
to the plane of movement of the slide button for moving the switch
between its respective "on" and "off" positions, means for
preventing withdrawal of the actuator from the switch in the "on"
position of the switch, and means operative in the "off" position
of the switch for allowing the actuator to be moved against the
force of the resiliently-biased means and sufficiently to clear the
slide button, whereby the actuator thereafter may be withdrawn from
the switch, thereby preventing an unauthorized operation of the
switch.
20. In combination with a switch having a sliding operating element
moving linearly in a plane between respective "on" and "off"
positions, a non-rotatable actuator slidably inserted into the
switch along a plane which is parallel to the plane of linear
movement of the switch operating element, resiliently-biased means
automatically operative upon the slidable insertion of the switch
actuator within the switch for effecting a "snap action" engagement
between the actuator and the switch operating element, the switch
actuator being pulled out to move the switch into its "on" position
and pushed in to move the switch into its "off" position, means
operative in the "off" position of the switch for allowing the
actuator to be moved against the force of the resiliently-biased
means and sufficiently to clear the switch operating element,
whereby the actuator may be withdrawn entirely from the switch,
whereby the switch operating element is thereafter completely
inaccessible, and whereby inadvertent or unauthorized operating of
the switch is thereby precluded, and means for preventing
withdrawal of the actuator in the "on" position of the switch.
21. In combination with a switch having an operating element with
respective "on" and "off" positions, a non-rotatable actuator
slidably inserted into the switch, resiliently-biased means
automatically operative upon the slidable insertion of the actuator
into the switch for effecting a "snap action" engagement between
the actuator and the switch operating element, the actuator
thereafter having a limited linear movement with respect to the
switch for moving the switch operating element between its
respective "on" and "off" positions, the actuator having an outer
operating portion enlarged laterally with respect to the actuator,
the enlarged operating portion being pulled out to move the switch
into its "on" position and pushed in to move the switch into its
"off" position, means operative in the "off" position of the switch
for allowing the actuator to be moved against the force of the
resiliently-biased means and sufficiently to clear the switch
operating element, whereby the actuator thereafter may be withdrawn
entirely from the switch, thereby precluding an unauthorized
operation of the switch, and means for preventing withdrawal of the
actuator in the "on" position of the switch.
22. In combination with a switch having respective "on" and "off"
positions and further having a switch housing, a switch actuator
received in the switch housing for moving the switch between its
respective "on" and "off" positions, the switch being of the
push-pull type, the actuator having an outer operating portion,
said portion having a substantially rectangular plan outline and
being enlarged laterally with respect to the actuator, said portion
being pulled out to turn the switch "on" and pushed in to turn the
switch "off", interlocking means between the actuator and the
switch housing for preventing withdrawal of the actuator from the
switch housing in the "on" position of the switch, and means
allowing the actuator to be withdrawn from the switch housing in
the "off" position of the switch, thereby precluding unauthorized
operation of the switch, said last-named means including an
accessible element carried by the actuator adjacent to the
operating portion of the actuator, said element being movable in
the "off" position of the switch and relative to the operating
portion of the actuator to move the actuator sufficiently to clear
the interlocking means between the actuator and the switch housing,
whereby the actuator may be removed from the switch in the "off"
position of the switch.
23. In combination with a switch having respective "on" and "off"
positions and further having a switch housing, a switch actuator
received in the switch housing for moving the switch between its
respective "on" and "off" positions, the switch being of the
push-pull type, the actuator having an outer operating portion
enlarged with respect to the actuator, the operating portion being
pulled out to turn the switch "on" and pushed in to turn the switch
"off", interlocking means between the actuator and the switch
housing for preventing removal of the actuator from the switch
housing in the "on" position of the switch, and means for
facilitating removal of the actuator from the switch housing in the
"off" position of the switch, thereby precluding unauthorized
operation of the switch, said last-named means including an element
carried by the actuator and disposed adjacent to the operating
portion of the actuator, said element being engageable by the
operator's thumb for movement laterally with respect to the
operating portion of the actuator, thereby moving the switch
actuator sufficiently to clear the interlocking means between the
actuator and the switch housing, and thereby allowing the actuator
to be withdrawn from the switch in the "off" position of the
switch.
24. In a table saw having a housing provided with a panel, and
further having a switch within the housing, the switch being
provided with an operating element for moving the switch between
its "on" and "off" positions, the operating element being movable
linearly in a given plane, the combination of a switch box mounted
on the front of the panel and projecting therefrom, a switch
actuator, means cooperating between the actuator and the switch box
for facilitating the slidable insertion of the actuator through the
switch box and within the housing, resiliently-biased means
operative upon the slidable insertion of the actuator for
automatically effecting a direct "snap action" engagement between
the actuator and the switch operating element, the actuator
thereafter having a limited slidable movement within the switch box
and in a plane substantially parallel to the plane of movement of
the switch operating element for moving the operating element
between its "on" and "off" positions, interlocking means between
the actuator and the switch box to prevent the actuator from being
withdrawn from the switch box in the "on" position of the switch,
and means operative in the "off" position of the switch for moving
the switch actuator against the force of the resiliently-biased
means and sufficiently to clear the interlocking means between the
actuator and the switch box, whereby the actuator thereafter may be
disengaged from the switch operating element, and whereby the
actuator may be withdrawn from the switch in the "off" position of
the switch.
Description
BACKGROUND OF THE INVENTION
In various types of machinery and powered equipment, such as a
table saw, it is desirable to preclude inadvertent or unauthorized
operation of the switch and hence the equipment controlled thereby.
In the prior art, of which I am aware, various means have been
provided to preclude such unauthorized operation.
For example, the switch may be of the simple toggle type, and a
u-shaped bracket may have its bight portion secured to the housing,
such that the legs of the bracket extend on respective sides of the
toggle. Each of the legs may have a hole formed therein, and with
the toggle in its down or "off" position, a simple padlock may be
inserted between the holes in the legs of the bracket and locked
therein. Movement of the toggle into the "on" position will
thereafter be precluded, until the padlock is removed.
Additionally, a key may be installed integrally on the machine,
adjacent to a separately-mounted switch actuator, and removal of
the key will preclude operation of the switch actuator from an
"off" to an "on" position. These mechanisms are usually arranged,
upon insertion of the key, to remove an internal barrier to
movement of the switch actuator to its "on" position.
Additionally, the art has resorted to a variety of lock buttons or
other locking members mounted within the switch actuator. For
example, the lock button may comprise a bifurcated plug member
having a pair of fixed prongs inserted into a receptacle in a
rocker-type switch. The plug member may be removed to preclude
pivotal movement of the rocker switch from its "off" position into
its "on" position. Others in the art have used a similar
pronged-type of removable lock button for a "pull on/push off"
switch, wherein the actuator may be provided with an enlarged outer
operating portion to facilitate its manipulation. Still others have
resorted to a lock button in conjunction with a pistol-grip type of
handle provided with a trigger switch; the lock button must be
continually depressed to enable the switch to be actuated by the
trigger. In this arrangement, the lock button may be removed to
prevent an inadvertent or unauthorized use of the switch. Finally,
the commercial art has disclosed an arrangement, wherein, the
switch is completely inaccessible to the operator upon removal of
the actuator.
The Peterson U.S. Pat. No. 4,107,484 is also illustrative of the
development of the art. In this patent, a key-type of actuator is
used with a rocker-type of switch. The key may be inserted into its
keyway and then rotated for proper orientation with respect to the
rocker switch. When so alined, the key may be pulled for moving the
switch into its "on" position and pushed for moving the switch back
into its "off" position. The key may be withdrawn from the switch
only in the "off" position of the switch.
These prior art disclosures and structures are relatively
complicated and sophisticated, hence expensive to manufacture and
to assemble into a power-operated machine. Additionally, the
stationary prongs of the plug-type keys may break off after
repeated and extensive insertions of the keys into the switch
actuator. Moreover, the switch may still be accessible, even after
removal of the lock button, and any internal blockage within the
switch may conceivably be over-ridden by the application of heavy
manual pressure on the accessible switch.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a
simple and economical actuator for a switch, one which is reliable
and convenient to use, wherein the switch is completely
inaccessible upon removal of the switch actuator.
It is another object of the present invention to provide a switch
actuator in the form of a bifurcated elongated member slidably
received within the switch, the member having a pair of legs
pivotable relative to each other in the "off" position of the
switch, thereby enabling the actuator to be completely removed from
the switch.
It is yet another object of the present invention to provide a
"pull on/push off" switch having a switch operating element in the
form of a simple and economical slide button, wherein the actuator
automatically engages the slide button upon insertion of the
actuator into the switch, and wherein the actuator moves linearly
in a plane parallel to the plane of motion of the slide button.
It is a further object of the present invention to provide a switch
actuator having an enlarged outer operating portion formed with a
longitudinal side edge having an arcuate cut-out, wherein the
actuator has a pivotable portion accessible via the cut-out for
facilitating removal of the actuator in the "off" position of the
switch.
It is a still further object of the present invention to enclose
the switch by means of a switch box mounted on the front of a panel
for the housing of a table saw, wherein the switch box has boss
means formed therein to facilitate the slidable insertion of the
actuator through the switch box to engage the switch, and wherein
interlocking means is provided between the switch box and the
actuator to prevent withdrawal of the actuator in the "on" position
of the switch, the interlocking action being avoided in the "off"
position of the switch to facilitate subsequent withdrawal of the
actuator.
In accordance with the teachings of the present invention, a switch
has an operating element with respective "on" and "off" positions.
A switch actuator is provided to prevent unauthorized operation of
the switch. The actuator is slidably received within the switch,
and upon insertion therein, automatically engages the switch
operating element. Thereafter, the actuator has a limited slidable
movement relative to the switch for moving the operating element of
the switch between its respective "on" and "off" positions. In the
preferred embodiment, the actuator comprises a bifurcated elongated
member having a pair of legs pivotable relative to one another. The
legs are biased to a first position, relative to one another, by
suitable resilient means. In the "off" position of the switch, the
legs may be pivoted against the resilient means to a second
position relative to each other; and thereafter, the bifurcated
elongated member may be withdrawn from the switch, thereby
preventing an unauthorized operation of the switch. When the switch
is in its "on" position, however, an interlock precludes the
relative pivotal movement between the legs, thereby precluding the
bifurcated elongated member from being withdrawn in the "on"
position of the switch.
These and other objects of the present invention will become
apparent from a reading of the following specification, taken in
conjunction with the enclosed drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of a table saw with which a preferred
embodiment of the present invention may find particular
utility;
FIG. 2 is a front elevation of the side panel of the table saw,
showing the switch box and the switch actuator mounted thereon.
FIG. 3 is a view, taken along the lines 3--3 of FIG. 2, but with
the switch actuator removed from the switch box and shown in
exploded elevation;
FIG. 4 is a stepped section view, taken along the lines 4--4 of
FIG. 3, and showing the switch actuator in plan view, the actuator
being formed as a bifurcated elongated member with a pair of legs
having a relative pivotal movement therebetween;
FIG. 5 is a front elevation o the switch box with the switch
actuator removed;
FIG. 6 is a section view, taken along the lines 6--6 of FIG. 4,
showing the pivot means between the legs of the bifurcated switch
actuator;
FIG. 7 is a section view, taken along the lines 7--7 of FIG. 4,
showing the complementary arcuate projection and recess formed on
the respective legs of the bifurcated member to facilitate pivotal
movement therebetween, and further showing the torsion spring
seated between the respective legs;
FIG. 8 is a plan view of the torsion spring in its relaxed
position;
FIG. 9 is an alternate embodiment of the resilient means between
the legs, comprising a leaf spring integrally molded on one of the
legs;
FIG. 10 is a section view, taken along the lines 10--10 of FIG. 4,
showing the operating portion of one leg accessible via the arcuate
cut-out formed in the enlarged operating portion of the other leg,
thereby facilitating a pivotal movement of the one leg with respect
to the other leg;
FIG. 11 is a section view, taken along the lines 11--11 of FIG.
10.
FIGS. 12a through 12d are schematic sequence views, showing the
manner in which the pivoted legs of the bifurcated switch actuator
automatically engage the slide button of the switch upon the
complete insertion of the actuator through the switch box to engage
the switch.
FIG. 13 is a top plan view, taken along the lines 13--13 of FIG. 2,
with parts broken away and sectioned, and showing the switch
actuator fully inserted into the switch, the switch being in its
"off" position;
FIG. 14 corresponds to FIG. 13, but shows the actuator pulled out
(away from the switch box) to move the switch from its "off"
position into its "on" position, the view showing the interlocking
means between the actuator and the switch box to prevent pivotal
movement between the legs, thereby preventing withdrawal of the
actuator in the "on" position of the switch;
FIG. 15 corresponds to FIG. 13, but shows the switch in its "off"
position with the actuator pushed back towards the switch box, and
further showing how the interlock is disabled to facilitate
relative pivotal movement between the legs of the actuator, the
arrow indicating the direction in which the switch actuator may be
removed;
FIG. 16 is a section view, taken along the lines 16--16 of FIG. 3,
drawn to an enlarged scale, and showing the slots (in the outer
boss of the switch box) forming part of the interlocking means;
FIG. 17 is a section view, taken along the lines 17--17 of FIG. 16,
showing one set of slots in plan outline;
FIG. 18 is a section view taken across the lines 18--18 of FIG. 3,
drawn to an enlarged scale, and showing a pin cooperating with the
slots to form the interlocking means; and
FIGS. 19a through 19c are schematic sequence views, corresponding
to FIGS. 13-15, respectively, and showing the function of the
interlocking means between the switch actuator and the switch
box.
DETAILED DESCRIPTION
With reference to FIG. 1, there is illustrated a table saw 10 with
which the teachings of the present invention may find particular
utility. It will be understood by those skilled in the art,
however, that the teachings of the present invention are not
necessarily confined to the saw, but are equally applicable to a
wide variety of switches and apparatus controlled thereby. With
this in mind, the saw 10, which is intended for use by contractors
and advanced home craftsmen, comprises a housing 11, supporting
feet 12 for mounting the housing on a bench or suitable platform, a
table top 13, a blade 14 projecting above the table, an elevation
control lever 15 movable in an opening 16, the lever adjusting the
extent to which the blade projects above the table (and in an
alternate mode of operation, for raising the blade up out of the
table to make a cut in a workpiece held securely on the table), a
bevel control lever 17 movable in a quadrant opening 18 for tilting
the saw blade relative to the table (from zero to forty-five
degrees) to make a bevel cut in a workpiece, and a switch assembly
19 mounted on a side panel 19a of the housing.
With reference to FIGS. 2 through 6, the switch is actuated by a
switch actuator 20 which comprises a bifurcated elongated member
having a pair of legs 21 and 22. These legs have respective first
and second portions, designated 21a, 21b and 22a, 22b,
respectively. A laterally-projecting boss is formed on each leg,
between its respective first and second portions. These bosses,
designated 23 and 24, respectively, are formed complementary to
each other and, as shown in FIG. 6, nest with respect to each
other. A pin 25 is received between the bosses, thereby pivoting
the legs with respect to each other. The respective first portion
21a of leg 21 has a blind arcuate recess 26 formed therein, as
shown more clearly in FIG. 4, and the respective first portion 22a
of leg 22 has a complementary arcuate projection 27 formed thereon
to be received in the arcuate recess. The projection and its recess
are formed about a radius from the pivot axis provided by the pin,
thereby facilitating the relative pivotal movement between the
legs. A torsion spring 28, shown in plan view in FIG. 8, has its
bight portion 28a seated adjacent to the pivot axis between the
legs, as shown more cleraly in FIG. 4, and further has respective
leg portions 29 and 30 seated in respective blind longitudinal
slots 31 and 32 formed in the respective first portions 21a, 22a
(of the respective legs 21, 22 of the bifurcated switch actuator)
thereby providing a resilient means between the respective first
portions of the legs. Alternatively, as shown in FIG. 9, the
resilient means may comprise an integrally-molded leaf spring 33
formed on one of the legs, bearing against the other leg, and
compressed thereby. In any event, the resilient means constantly
urges the respective first portions 21a, 22a apart, and conversely,
constantly urges the respective second portions 21b, 22b
together.
With reference again to FIGS. 2 through 4, the switch assembly
further includes a switch box 34 secured to the side panel 19a of
the saw. This switch box is preferably rectangular in plan outline
and is raised away from the panel. An outer boss 35 is formed on
the front of the switch box, and an inner boss 36 is formed within
the switch box, the inner boss being formed as a partial
continuation of the outer boss as shown more clearly in FIG. 4. The
outer boss has a longitudinal slot 37 formed therein, as shown in
FIG. 5, to receive a complementary longitudinal ridge 38 formed on
the leg 22. As a result, when the switch actuator is inserted into
the switch box, the leg 22 is restrained against pivotal movement.
Additionally, the outer boss has a side wall 39 adjacent to its
slot 37, and the inner boss has a side wall 40 formed coplanar with
the side wall 39 of the outer boss. The leg 22 has a flat side
surface 41 which bears against the coplanar walls 39, 40 of the
respective bosses. Thus, the leg 22 is restrained against pivotal
movement, while the leg 21 is free to pivot relative to leg 22.
With reference again to FIGS. 2 and 3, and with further reference
to FIGS. 10 and 11, the leg 22 has an outer operating portion 42
formed integrally therewith. This operating portion 42 is
preferably formed as a rectangle in plan outline, as shown in FIG.
2. The portion 52 is enlarged and extends laterally of the boss and
parallel to the switch box for convenient use by the operator. An
arcuate cut-out 43 is formed along a longitudinal side edge 44 of
the enlarged operating portion 42, and a blind transverse recess 45
is formed in the underside of the enlarged operating portion 42
adjacent to the arcuate cut-out 43. The one leg 21, which pivots,
also has an integrally-formed operating portion 46 (of smaller
dimensions than the enlarged operating portion 42 of the other leg
22). This operating portion 46 is seated partially in the blind
transverse recess 45 and is accessible via the arcuate cut-out 43
in the enlarged operating portion 42.
In operation, the user may grasp the enlarged operating portion 42
with his fingers, and with his thumb depress the operating portion
46 of leg 21 further into the blind transverse recess 45, thereby
pivoting leg 21 relative to the non-pivotal (fixed) leg 22 to
facilitate the subsequent withdrawal of the switch actuator 20 from
the switch assembly.
With reference to FIGS. 12a through 12d, it will be appreciated
that when the switch actuator 20 is slidably received into the
switch assembly, and fully seated therein, the switch operating
element comprising the slide button 47 is automatically engaged by
the switch actuator. Thus, FIG. 12a shows the initial engagement
between the switch button 47 and the respective inner ends of the
legs 21, 22. As the switch actuator is moved further into the
switch assembly, the switch button 47 engages the chamfered edge 48
of the pivotal leg 21, thereby pivoting the leg 21 against the
force of the torsion spring. When the actuator is moved still
further, the leg 21 has pivoted its maximum amount, as shown in
FIG. 12c, and thereafter the chamfered edge 48 rides up over the
switch button 47, the leg 21 pivots back in an opposite direction
under spring action, and the switch button is thereby received in a
transverse notch 49 formed at the end of chamfered edge 47. The
switch button 47 is thereby automatically engaged by the switch
actuator 20, as the actuator is slidably received in the switch
assembly, and a "snap action" is achieved by means of the torsion
spring.
With reference to FIG. 13, the switch actuator 20 is fully seated
within the switch assembly 19 and has engaged the switch button 47.
The actuator is shown in its innermost (retracted) position within
the switch assembly and with its operating portion 44 adjacent to
the outer boss 35 on the switch box 34, which is the "off" position
of the switch. The actuator has a limited linear movement in a
plane parallel to the plane of movement of the switch button 47. As
shown in FIG. 14, the actuator has been pulled out (and away from
the switch box) to move the switch from its "off" position into its
"on" position, the switch being of the "pull on/push off" type.
Preferably, the switch button is part of a simple (and inexpensive)
slide switch, designated as at 50, and the switch is mounted within
the housing by means of a bracket 50a.
With reference to FIGS. 14 through 18, the outer boss 35 of the
switch box has a pair of slots 51 and 52 formed therein. These
slots are separated by a side ridge 53. Slot 51 is open, while slot
52 is closed by an end ridge 54. These slots and ridges cooperate
with a pin 55 carried by the pivotal leg 21 and extending
therefrom. Preferably, the pin extends from both the top and bottom
of leg 21, and similar slots are formed on both the top and bottom
of the outer boss 35.
With reference again to FIGS. 14 through 18, and with further
reference to FIGS. 19a through 19c, the pin and slots cooperate to
form an interlocking means to preclude relative pivotal movement
between the legs 21, 22, and hence preclude withdrawal of the
bifurcated switch actuator 20 in the "on" position of the switch.
Thus, as shown in FIGS. 14 and 19a, the switch is in its "on"
position, and the pin 55 is received all the way down in the closed
slot 52 adjacent to the end ridge 54. In this position, the leg 21
carrying the pin 55 cannot be pivoted, and hence the actuator
cannot be removed from the switch. As shown in FIGS. 15 and 19b,
however, the switch is in its "off" position, and pin 55 is still
in the slot 52 but beyond the side ridge 53. In this position, the
leg 21 may be pivoted, moving the pin 55 to the open slot 51 as
indicated in FIG. 19c. Thereafter, the actuator may be removed from
the switch, as indicated by the arrow, to the position shown in
FIG. 3. The actuator 20 may be retained and safeguarded by the user
to prevent an unauthorized or inadvertent operation of the switch
and hence the table saw 10.
To re-insert the actuator within the switch box, the legs are again
pivoted relative to each other, so that the pin 55 is received
within the open slot 51, and with the actuator properly oriented
for cooperation between the longitudinal ridge 38 and its
cooperating slot 37.
Obviously, many modifications may be made without departing from
the basic spirit of the present invention. For example, both legs
could be adapted to pivot if desired. Accordingly, it will be
appreciated by those skilled in the art, that within the scope of
the appended claims, the invention may be practiced other than has
been specifically described herein.
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